A civilian U.S. Coast Guard employee was placed on paid administrative leave, threatened with a criminal investigation and confronted by guards at gunpoint in retaliation for disclosing information embarrassing to the service's troubled fleet replacement program, his attorney said.

Anthony D'Armiento, a former Northrop Grumman systems engineer working for the Coast Guard's acquisitions department, asked the Bush administration to appoint an independent inspector general to investigate his allegations against staff members of Richard L. Skinner, inspector general of the Department of Homeland Security. D'Armiento's attorney called their actions "an egregious act of intimidation and excessive force" against a government whistle-blower.

D'Armiento was placed on leave Oct. 1 and told to cooperate with Coast Guard investigators or face criminal prosecution, said Debra S. Katz, his attorney, in a letter to Skinner and the White House.

D'Armiento cooperated, but after he was told he could retrieve his office and home computers from Skinner's offices in Rosslyn on Oct. 29, Paul Weare, an investigator for the DHS inspector general, attempted to question D'Armiento. When D'Armiento refused to answer, three guards appeared, one pointed a gun at his chest, denied him his equipment and threatened him with arrest if he returned, Katz said.

"Mr. Weare was trying to lure Mr. D'Armiento to the OIG office where he could be further interrogated without his attorney present," Katz said in the letters, copies of which were obtained by The Washington Post. "This staged armed confrontation was an extreme and transparent act of retaliation against Mr. D'Armiento."

Skinner's office did not respond to repeated requests for a comment. A DHS official confirmed that D'Armiento is under investigation.

The Coast Guard said in a statement that "unauthorized disclosure or improper handling of sensitive, classified or proprietary information is strictly prohibited and may result in administrative or criminal charges."

Katz wrote that when D'Armiento declined to speak with Weare in an interrogation room and said, "I want my computer back now," Weare told him to "back off" and "get out of [his] face." After a guard drew his handgun, prompting D'Armiento to say he would call the police, a guard replied, "We are the police," Katz wrote.

Katz said that, on Sept. 25, D'Armiento turned over to a fellow whistle-blower Coast Guard documents marked sensitive but unclassified, and that the papers showed that the agency was aware of hundreds of defects in communications equipment aboard its new, $640 million flagship vessel, known as the National Security Cutter. The ship is part of the Coast Guard's $25 billion fleet replacement program, known as Deepwater.

In the documents, dated August and September and reported by Wired magazine's Web site, Coast Guard officials noted the probability that the first of eight planned cutters "will be unable to process classified information." Nevertheless, the Coast Guard appeared prepared to accept responsibility for correcting some defects at added taxpayer expense after delivery, even though that was the contractors' obligation, D'Armiento alleged.

Coast Guard officials called the criticism premature. They said the authorities were aware of the reported defects. "We're not going to accept [delivery of] a cutter with any kind of major problems," Coast Guard spokeswoman Laura Williams said.

The vessels are being built by Northrop Grumman with electronics provided by Lockheed Martin. The first cutter, the Bertholf, whose price tag has doubled since 2002 and whose delivery was delayed from August to April, is undergoing trials at sea. The second and third of eight planned ships are under contract, estimated to cost $500 million each.

The Coast Guard is also addressing design flaws that could lead to fatigue cracks well before the end of the first cutter's 30-year life span.